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An optical clock based on a single trapped 199Hg+ ion
S A Diddams1, T Udem, J C Bergquist
1Time and Frequency Division, National Institute of Standards and Technology, 325 Broadway, Boulder, CO 80305, USA. sdiddams@boulder.nist.gov
Science (New York, N.Y.)
|July 14, 2001
Summary
Researchers developed an all-optical atomic clock using a single trapped mercury-ion (199Hg+) for superior timekeeping. This optical atomic clock demonstrates significantly better stability than current microwave atomic clocks.
Area of Science:
- Atomic, Molecular, and Optical Physics
- Metrology and Measurement Science
Background:
- Microwave atomic clocks have been primary standards for time and frequency for 50 years.
- Optical atomic clocks offer potential for higher stability due to their higher operating frequencies.
Purpose of the Study:
- To demonstrate an all-optical atomic clock.
- To achieve enhanced frequency stability beyond microwave standards.
Main Methods:
- Utilized a single trapped 199Hg+ ion, referencing a 1.064-petahertz transition.
- Employed a mode-locked femtosecond laser clockwork, phase-coherently locked to the optical frequency.
- Compared performance against a laser-cooled calcium optical standard.
Main Results:
- Achieved a fractional frequency instability upper limit of 7 x 10(-15) at 1 second averaging time.
- Demonstrated stability substantially exceeding that of the best microwave atomic clocks.
Conclusions:
- All-optical atomic clocks based on optical transitions offer superior stability.
- The demonstrated 199Hg+ ion clock represents a significant advancement in precision timekeeping technology.
